1. Field of the Invention
The present invention relates to a recording apparatus that records by recording means mounted on a carriage.
2. Related Background Art
Conventionally, a recording apparatus of a serial type that records on a recording medium by causing its recording head to travel (to execute the main scans) comprises a carriage that mounts the recording head on it to reciprocate (to execute the main scans); a guide unit that guides the carriage to reciprocate; a carriage driving motor (referred to as a CR motor) that enables the carriage to execute the main scans; and a power transmission mechanism formed by pulleys, a transmission belt, and others that transmits the driving power of the CR motor to the carriage.
For an apparatus of the kind, it is necessary to suspend recording once if a clogging (jamming) of a recording sheet (a recording medium) takes place during recording, and then, after such clogged sheet is removed, the recording is resumed. In this respect, if the carriage comes to a stop in the recording area, that is, on the recording sheet at that time, a procedure should be taken so that the carriage is allowed to move outside the recording sheet, at first, and then, the clogged recording sheet is removed.
Meanwhile, as the CR motor, a stepping motor or a DC motor is generally used. The stepping motor has a property that its holding torque is extremely small when it is not excited. Also, the DC motor has a property that its holding torque is extremely small, because it is not structured to effectuate any holding. Therefore, the recording apparatus that uses either a stepping motor or a DC motor as its CR motor makes it easier to move the carriage by the application of a small force.
However, if an ultrasonic motor (hereinafter referred to as a USM) is used as a carriage driving motor (CR motor) for the conventional recording apparatus, there is a problem that the carriage cannot be moved easily by a manual operation, because the rotor and stator of a USM are in contact under pressure, which results in a greater holding torque as compared with the stepping motor or the DC motor.
In other words, since the holding torque of the USM is great, the USM itself does not move even if it is intended to manually move the carriage provided for the recording apparatus that uses the ultrasonic motor as its CR motor. As a result, a problem is encountered that the coupling portion between the carriage and the transmission belt is damaged, the belt is broken, or the pulley shaft is deformed, among other possible damages.